Some customers are reporting an AT&T outage on Tuesday, with some saying their phones have been stuck in SOS mode over several hours and unable to access service.

Reports of a potential AT&T service disruptions to the website Downdetectorbegan to spike just after 4 p.m. ET, with as many as 5,800 reports made by 6:46 p.m. ET and more reports continuing to come in Tuesday evening.

“We are working as quickly as possible to address a software issue that may be disrupting the ability of some of our customers to connect to our wireless network,” an AT&T spokesperson said in a statement to USA TODAY. “Keeping our customers connected is our highest priority, so we appreciate their patience as we work to resolve this issue.”

The issue appears to be affecting wireless customers in the Midwest and East, the spokesperson said.

What does SOS mode mean on your phone?

For AT&T customers who may be experiencing an outage Tuesday, an SOS symbol may appear on the screens of iPhone users in the same place where cell service bars are normally shown.

USA TODAY previously reported that the SOS symbol can appear in the status bar of iPhones and iPads, meaning devices aren’t connected to a cellular network. It also means there is a cellular network “available for emergency calls,” Apple’s support website states.

The SOS feature is available on iPhones and iPads in the U.S., Australia and Canada.

“When you make a call with SOS, your iPhone automatically calls the local emergency number and shares your location information with emergency services,” according to Apple. “In some countries and regions, you might need to choose the service that you need.”

After making an emergency call, your iPhone alerts any emergency contacts designated in your phone.

Apple says all iPhone models 14 or later can also use Emergency SOS via satellite to text emergency services when no cellular and Wi-Fi coverage is available.